Bicymple

I have loved David Thompson’s Friday ephemera postings ever since they started, and the latest list contains something I especially enjoyed finding out about.

You wouldn’t think it would be possible to make the bicycle an order of magnitude more simple, but it would appear that the bicymple is just that. Instead of that big triangular bicycle frame in the middle, they just have a single strut across the top. The wheels are as near to each other as they can be without bumping into each other. The pedals of the bicymple are attached to the middle of the back wheel, which gets rid of the chain.

Unridable? Well, here is a video of a guy riding it. And here is an interview with the inventor.

The world is full of bizarre transport gadgets that “work”, in the merely mechanical sense, but which nobody seems to want to use for anything other than pratting about in pointlessly. So, whether the bicymple will ever catch on in a significant way is anybody’s guess. My guess is a definite maybe. I will sit decisively on the fence, and wait to see what happens with this strange little contraption.

All I can say with certainty is that I am looking forward to reading any guesses about the possible future of this bizarre gizmo that our often very tech-savvy commentariat feels inclined to offer.

October 14th, 2012 |

14 comments to Bicymple

I suspect that with the wheels that close together that it is stiff and sends every bump straight to the rump. It also looks like it would be touchy to steer, and the sitting position is probably a bit upright for long rides.

Hmmm. This thing is in unicycle territory. Some of the development needed for gearing the driving wheel can definitely be taken from existing unicycles, so there’s that. This might also be a good starting point for making a half-decent chainless tandem bike. That wouldn’t have the balance stability problems that this one looks like it has. Watching the video — not a great vid BTW, doesn’t show you enough about the bike and seems all about the swing mode of the rear wheel — makes me wonder if it might not be better to make the front wheel the driving wheel and have the rider lean back recumbent or semi-recumbent; IOW, a chainless recumbent bicycle. I do like the attempt at innovation.

The “ordinary” or “penny-farthing” bicycle had a large front wheel, limited in size by the length of the rider’s legs, to allow a higher gear. Unfortunately, this raised the center of gravity even as it shortened the wheel base, making it easier to take a “header” by falling forward over the handlebars. Hence, the chain-drive bicycle with two equal wheels and a longer wheel base was known as the “safety” bicycle. The bicymple’s shorter wheel base might make it oversteer compared to safety bicycles and increase the risk of header accidents.

The overdrive hub is another surprise. It is currently in development and has caught the attention of many in both the bicycle and unicycle communities. The classic thinking is that the only way to go faster with a direct coaxial drive is to increase the size of the wheel, which was the famous fatal flaw of the penny farthing. A few clever designs out there for unicycles have gotten around this but at quite a price. We’ll be able to accomplish the same goal at a price that should be quite affordable. It’s a compact, sealed, zero-service unit so you’ll never have to think about it–and it certainly won’t get your pants leg greasy!

He seems to have read your mind, Antagonist:-) From that same link (helpfully provided by Brian in his original post):

The things that set it apart and make it special are obviously the rear steering, but also the fact that the rear steering can be locked out, allowing it to be ridden just like a regular bike. Many comments out there on the web overlook this key fact.

When I was a kid, one of my friends had a bike with “unlocked” rear wheels like this. We called it his “clown bike.” It was a typical 1-speed kid’s bike with a chain drive and “pedal backwards to brake,” and the whole drive assembly swung with the back wheel.

It took a bit of getting used to, but after 15 minutes or so you didn’t even notice that the back wheel could twist and turn…. unless you got going up to speed and let it wiggle a little bit, in which case you were guaranteed to wipe out.

You could lock the back wheels also, but there was a little bit of “give” on it when it was locked in, so it was actually easier to ride with it unlocked. Assuming you didn’t get much above 10 mph, anyway.

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